Try opening the files from within Excel. In the file browse form, look at the file type. Foxpro files are based on dbase, so you might be able to use that option.
If you don't have the odbc drivers/oledb providers installed, re-install Excel; you have the option of adding additional drivers/providers in the custom install.
Now, depending upon your MS Office version (Office 2002 or greater,) you may need to use the FoxPro ODBC driver. Ref this MS KnowlegeBase article (http://support.microsoft.com/kb/286224). (although this link is specific to Access, it should also work for Excel) I would recomend that create a file dsn using the FoxPro ODBC driver, and store it in an easily accessible location.
Then, from Excel, one of the file open dialog file type options is for "All Data Sources," which includes DSN files.